Gimbal systems for contemporary seeker missile use have progressed beyond classic two ring gimbal systems. The demands for fast response time, wide look angles, low cost, low swept volume and accuracy have been met by systems such as the one described in "STABILIZED PLATFORM SYSTEM" U.S. Pat. No. 4,068,538 by Butler et al. and "OBLIQUE AXIS SEEKER", patent application Ser. No. 943,598 by Reid, both assigned to the assignee of the instant invention. Each of these systems has contributed to the state of the art in terms of operating capabilities and low cost implementation. The Butler et al. system, supra, utilizes a complex of coupling devices and structure to support the platform. Each of these components contributes off center mass which increases the inertia of the system. The component count is relatively high which tends to decrease reliability, decrease useable servo system bandwidth and to increase cost of fabrication and assembly. The swept volume of this system is very low, however.
The Reid system, supra, employs substantially non-orthogonal axes to accomplish continuous motor operation without need for motor reversal in a search or sweep mode of operation. However, this system also suffers from high inertia due to the geared linkage and, in some configurations, it may be prone to gimbal lock-up within a desired range of "look" angles. The non-orthogonal axes configuration requires a complex mathematical conversion for operating an X/Y axis control fin system.